This invention relates to a gas driven gyroscope with an integrally contained gas source. More particularly it relates to improvements in gas driven gyroscopes which extend the rundown time or maintain higher speeds of the rotor during a specified time.
Gas driven gyroscopes with integrally contained gas sources are known which have a gas driven reaction rotor in one chamber and compressed inert gas in another chamber. Gas is released from one chamber by means such as puncturing a thin wall between the chambers. The gas, when released, flows through the hollow bore of the rotor shaft and outwardly through reaction passages in the rotor to cause it to spin. Changes in the gas pressure may also uncage the gyroscope gimbals after the rotor is spinning.
An example of the foregoing type of gas driven gyroscope is fully detailed in U.S. Pat. No. 3,393,569 issued July 23, 1968 to Lawrence J. Lief and assigned to the present assignee. The Lief patent is incorporated herein by reference and any of the various species of gas driven gyros shown in the Lief patent might employ the improvement of the present invention.
One advantage of a gas driven gyro, as compared to spring driven gyroscopes, is that it has a high ratio of usable energy in relation to its volume and weight. The potential energy in the compressed gas is quickly translated to rotational kinetic energy of the spinning rotor. The "rundown" of the rotor refers to the gradual decrease in rotor speed over time after the gas is expelled through the rotor passages. Various losses affect the rundown. One loss is caused by the reaction rotor acting as a pump rather than as a reaction turbine and acting to suck gas through the end of the shaft and pump it out the rotor exhaust ports thus reducing energy and causng more rapid slowing down of the rotor.
Accordingly, one object of the present invention is to provide an improved gas driven gyroscope with an extended rundown time, or having a higher average speed during a specified rundown time.
Another object of the invention is to provide an improved gas driven gyroscope with reduced losses during rundown.
Another object of the invention is to provide an improved device to shut off gas flow in a gas driven gyroscope with a reaction rotor.